Method of preparing triesters



United States Patent 3,278,581 METHOD OF PREPARING TRIESTERS Paul M. Kerschner, Trenton, N..l., assignor to Cities Service Oil Company, a corporation of New Jersey No Drawing. Filed Sept. 19, 1963, Ser. No. 310,158 3 Claims. (Cl. 260-468) This invention relates to novel synthetic polyester lubricants. More particularly this invention is directed to certain polyesters of cyclopropane and their method of preparation.

Presently available mineral hydrocarbon lubricating oils widely used in conventional internal combustion engines have limited application under the rigorous conditions at which many of the more modern engines, e. g. jet engines, operate. Conventional hydrocarbon oils also suffer from numerous shortcomings including unsuitability for use at high pressures and temperatures.

The inherent disadvantage of mineral hydrocarbon lubricating oils have generally made them unsuitable for jet and turbo-jet engines now used to power modern aircraft. In recent years a series of synthetic lubricants have become available to overcome some of the disadvantages of hydrocarbon lubricants. These new synthetic lubricants are generally characterized by lower changes in viscosity at increasing temperatures, high stability to oxidation, low pour point, high flash point and good extreme pressure properties.

Accordingly an object of this invention is to provide a new series of polyester lubricants which overcome inherent disadvantages of mineral hydrocarbon lubricating oils.

It is another object of the present invention to provide a class of new polyesters suitable as lubricants for high temperature and extreme pressure use which have high stability to oxidation, at high flash point, good viscosity, relatively high viscosity indices, and relatively low pour points.

Other objects and advantages of the novel polyesters of the present invention, together with the methods by which they are made will be readily apparent from the detailed description which follows.

The novel polyesters of the present invention can be represented by the following generic formula:

- R1 0: -OR

wherein each R is alkyl having from 1 to about 18 carbon atoms and R is hydrogen or methyl. Preferably each R is alkyl having from 1 to 6 carbon atoms and R is hydrogen. Each alkyl can be straight or branched chain and the number of carbon atoms of each alkyl group of the above formula can vary.

The polyesters of the present invention are prepared by contacting an alph-a-halo-acid alkyl ester with an itaconic acid alkyl diester in the presence of a base condensation catalyst. The alpha-halo-acid alkyl esters can be represented by the formula:

mx-ii-oR wherein R is methyl or ethyl, R is alkyl having from 1 to about 18 carbon atoms and X is a middle halogen, i.e. chlorine or bromine which is attached to the carbon atom adjacent the carbonyl radical.

The itaconic acid alkyl diesters can be represented by the formula:

Patented Oct. 11, 1966 ice wherein each R is alkyl having from 1 to about 18 carbon atom-s. The R (alkyl) groups of the itaconic acid diesters and the alpha-haloacid esters, are of course the same R groups shown in the generic formula of the novel polyesters and each have the same or a different number of carbon atoms in a straight or branched chain configuration, preferably with each R group having from 1 to 6 carbon atoms. Illustrative of the base condensation catalyst there can be mentioned those of basic oxides, hydroxides, alkoxides, hydrides, cyanides, amides of alkali metals, alkali metals, and other basic material such as aralkyl quaternary ammonium hydroxides. Preferred base condensation catalysts are sodium methox-ide, sodium hydride dispersed in oil and benzyl trimethyl ammonium hydroxide.

It is preferred that the novel polyesters be prepared by intimately admixing the two reactants and the catalyst at temperatures of from about 15 C. to about 35 C. The molar ratio of the reactants can vary over a wide range. Preferably a molar excess of the itaconate reactant is employed such as from about 1.1 moles of the itaconate and particularly from about 1.5 to 6 moles thereof for each mole of the haloacid ester. The quantity of base condensation catalyst should be sufficient to react with all of the halogen in the haloacid ester. Thus equal molar quantities of the alpha-haloacid ester and base condensation catalyst are preferably employed although the molar ratio of either one to the other can vary, e.g. from about 0.5 to 2 moles. The novel polyesters can be recovered from the reaction mixture by conventional techniques such as fractional distillation. Surprisingly however, it has been found that other unsaturated disbasic acid esters in place of the itaconate diesters are inoperable in this above method of preparation. Thus, the substitution of diethyl fumarate for diethyl itaconate in the above method produced a dark colored tar.

Typical of the diesters of itaconic acid there can be mentioned those of dimethyl, diethyl, dibutyl, diamyl, dihexyl, diheptyl, dioctyl, dinonyl, didodecyl, ditetradecyl, distearyl, butylamyl, hexyloctyl, and the like. Typical alpha-haloacid esters are those of ethyl chloroacetate, butyl chloracetate, hexyl alpha-chloropropionate, octyl chloroacetate, nonyl alpha-chloropropionate, tetradecyl' Example 1 Into a four neck, two liter flask equipped with a mechanical stirrer, reflux condenser, thermometer, and a powder addition funnel is placed 334 grams (1.45 moles) of din-butylitaconate and grams (0.61 mole) of ethyl chloroacetate. While stirring vigorously, 33 grams (0.61 mole) of sodium methoxide was added at such a rate as to maintain a temperature of from about 20 C. to 30 C. After all of the sodium methoxide was added, vigorous stirring was continued and the reaction allowed to go on for an additional 1.5 hours. The reaction mixture was then transferred to a separatory funnel and approximately 200 ml. of toluene was added. To this solution 500 ml. of a saturated sodium chloride solution was added and the mixture shaken vigorously. The aqueous salt layer was drained off and discarded. The organic phase was treated an additional three times with a saturated salt solution. The organic phase was then dryed over anhydrous calcium sulfate. The dryed reaction mixture was transferred to a two liter round bottom distillation flask and the excess itaconate and solvent toluene were recovered by distilling at moderately reduced presa) sure. By fractionally distillation at a temperature of from 103 C. to 105 C. at 55 milimeters of mercury there were collected the polyester of the formula:

H O: --O(CH2)3-CH3 The properties of this polyester are listed below:

Example 2 The wear characteristics of the polyester of Example 1 were determined on the Shell four ball wear machine and compared with that of 100 neutral mineral oil. The results of this test are reproduced below.

Scar Diameter When Using the Polyester of Example 1 Scar Diameter When Using 100 Neutral Weight A plied p Mineral Oil It can be seen from Example 2 that the synthetic lubricants of this invention have good extreme pressure properties.

Example 3 Following the procedure employed in Example I the corresponding polyesters of the following reactants With the indicated catalysts can be prepared: (a) 224 grams (1.0 mole) of di-Z-ethylhexyl itaconate, 89 grams (0.5 mole) amyl alpha-chloropropionate, and 12 grams (0.5 mole) sodium hydride; (b) 280 grams (1.0 mole) didecyl itaconate, 103 grams (0.5 mole) 2-ethylhexyl chlorylacetate, and 12 grams (0.5 mole) sodium hydride (dispersed in oil) (c) 448 grams 1.0 mole) distearyl itaconate, 96 grams (0.5 mole) hexyl alpha-chloropropionate, and 20 grams (0.5 mole) potassium hydride (dispersed in oil); and (d) 60 grams (0.318 mole) dimethyl itaconate, 32 grams (0.260 mole) ethyl chloroacetate and grams (0.18 mole) sodium methoxide.

Example 4 This example shows a suitable blend of lubricating composition containing a synthetic lubricant of this invention and a conventional mineral hydrocarbon lubricating oil.

Percent Mineral lubricating oil (100 neutral) 10 Polyester of Example 1 90 Total 100 oils of either naphthenic or parafiinic origin. When employed in combination with mineral hydrocarbon lubricating oils the quantity of the triesters can vary from 5% to 95% by weight of lubricant composition which can also contain from 5% to 95 by weight of the mineral hydrocarbon oil, although it is preferred that the final lubricating composition contain from about 5% to 50% by Weight of the mineral hydrocarbon lubricating oil and from about 95% to 50% by weight of the novel polyesters of this invention, and particularly such a composition should contain at least by Weight of the novel polyesters in order to better take advantage of their desirable properties.

While the invention herein has been described in considerable detail with respect to certain preferred embodiments, it is to be understood the variations and modifications can be made which will fall Within the scope of the invention described above and as defined in the claims which follow.

What is claimed is:

1. The method for preparing a polyester of cyclopropane which comprises:

(a) contacting an alkyl diester of itaconic acid of the formula:

oH2=oCH,-C-oR wherein each R is alkyl having from 1 to about 18 carbon atoms; with (b) an alpha-halo-ester of the formula wherein R is a member selected from the group consisting of methyl and hydrogen, R is alkyl having from 1 to about 18 carbon atoms and X is a middle halogen; in

(c) the presence of a base condensation catalyst.

2. The method for preparing a polyester of the formula which comprises: (a) admixing di-n-butylitaconate with; (b) ethylchloroacetate at a temperature of from about 15 C. to about 35 C. wherein from about 1.5 to 6 moles of the itaconate are admixed with each mole of the chl-oroacetate in the presence of a catalytically effective quantity of a base condensation catalyst.

3. The process of claim 2 wherein the base condensation catalyst is sodium methoxide.

References Cited by the Examiner UNITED STATES PATENTS 3,010,990 11/1961 Kerschner 25257 OTHER REFERENCES DANIEL E. WYMAN, Primary Examiner. W. CANN N. Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,278,581 October 11, 1966 Paul M. Kerschner It. is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the heading to the printed specification, line 4, for "a corporation of New Jersey" read a corporation of Delaware Signed and sealed this 29th day of August 1967.

(SEAL) ERNEST W. SWIDER EDWARD J. BRENNER Awesting Officer Commissioner of Patents 

1. THE METHOD FOR PREPARING A POLYESTER OF CYCLOPROPANE WHICH COMPRISES: (A) CONTACTING AN ALKYL DIESTER OF ITACONIC ACID OF THE FORMULA: 